Memorandum presenting the rules and regulations of the Endurance Contest of Aviation Engines, which was put on by the Aero Club of France. A description of the rules regarding the aircraft in competition, the characteristics of the tests that were conducted, and information regarding classification of the aircraft is provided.

Static soaring flight has hitherto been accomplished by means of two sources of energy: ascending air currents in the vicinity of obstacles and those produced by unequal heating. The latter has not yet been practically tested in soaring flight.

"These notes are intended to furnish practical and general data on the effect of altitude on engine power. The effective horsepower of an engine is a function of the mean pressure of the fluid acting on the pistons, of the R.P.M. of the engine and of the mechanical efficiency" (p. 1).

The designing of an airplane requires an accurate knowledge of the aerodynamic properties of its wings, as expressed in the polar diagram. It is important to continue the theoretical researches on the aerodynamic phenomena of wings, in order to determine by calculation, their fundamental characteristics and to increase and formulate our knowledge in this field.

Memorandum presenting a method of calculating the dead reckoning in aerial navigation.

Different aspects of an airship line between Lisbon and Rio de Janeiro are presented. Some of the factors discussed are: the number of passengers, fuel consumption, design, itinerary, airports, flight times, and income.

The structural details such as wings, fuselage, landing gear, and steering organs of German gliders are detailed in this report.

The calculations in this paper afford an approximate solution of the static stability. A derivation of the formulas for moment coefficient of a wing, moment coefficient of elevator, and the total moment of the combined wing and elevator and the moment coefficient with reference to the center of gravity are provided.

This paper calls attention to the desirability of expanding airplane building regulations to include proof of safety for cases of unsymmetrical loading, at least in the structural members which are thereby specially stressed. The flight cases involve increases of the customary load assumptions through rudder deflection and aileron deflection.

In order to understand the numerical relations between the air velocity, temperature of the cylinder walls, heat dissipation, cylinder dimensions and type of construction an experimental plant was installed in the Siemens and Halske laboratory. The experimental cylinder was exposed to the air stream of a wind tunnel. The compression chamber was heated by an electrically heated oil bath kept constantly in motion by a stirrer. The wall temperatures were measured by thermocouples.

Memorandum presenting the history and development of airships. Tables containing information and statistics regarding some of the current airships are provided.

This article presents a discussion of the relative merits between monoplanes and biplanes. A comparison of the aerodynamic qualities and advantages of both types are provided.

Report describing the development of the racing airplane and some of the types of airplanes that might be seen at the Detroit airplane races. The primary contribution of racing aircraft to general aircraft development is the modification in design that makes it possible to cut down the resistance to motion through the air.

Report presenting some of the early history of metal aircraft construction and its advantages over other types of materials.

"The Boerner airship is built on entirely different principles from ordinary airships, of which the Zeppelin is the best known type. Mr. Boerner has abandoned the rigid body of the Zeppelin and has adopted a body with a double keel forming a rigid platform for attaching the gas ballonets, which must support the whole in the air" (p. 1).

"A device which does for the aircraft what change speed gears do for the automobile is the invention of Spencer Heath. It comprises a system of special blades and a mechanism for varying the pitch of the blades from zero to 360 degrees, while in flight or otherwise. By adjusting the pitch, either before starting or while the engine is running, to a less than normal angle, the engine is allowed to pick up speed and deliver its maximum power which is necessary in taking-off with a heavier load than the same airplane could otherwise normally carry" (p. 1).

Report presenting an examination of the errors that result from testing an aircraft model and applying the results to full-sized airplanes. An investigation is carried out to determine how to obtain comparable polars regardless of whether the supports are attached to the upper or lower side of the model.

In the present state of things, there are three great problems to be solved, relating respectively to the financial, technical, and commercial aspects of the question of commercial aviation.

An aircraft freed from all contact with the ground during most of the period of its operation, is nevertheless dependent on the provision of proper ground organization. The provision of landing fields scattered over the country for the benefit of civil or military pilots who may arrive from any direction constitutes the first step in making commercial flying possible.

The marketing and advertising of air transport is discussed in this article.

The engine of a commercial airplane must, above all, be sure and durable. It seems therefore, that we must use engines with vertical cylinders or in the V form with quite a small angle.

Different methods of presenting aeronautical artifacts are examined. The advantages of operating an aeronautical museum and its ability to increase public interest in aircraft are provided.

Stunting is an important part of the training of a military pilot, and the knowledge gained in passing through the "acrobatic course" is put to constant use in service, especially with fighting aircraft.

Report describing some information that has been learned from three different glider meets. While light loading was assumed to be the optimal conformation from previous meets, subsequent meets have shown that heavier loading produced better results.